The goal of this proposal is to identify and understand the risks associated with environmental sources that may provide a conduit for avian influenza virus (AIV) transmission from avian species to humans. There are three broad aims: 1) To estimate potential AIV loads associated with environmental sources of potential public health significance and to identify the factors that may enhance or limit persistence of AIVs in these sources; 2) To conduct a quantitative risk assessment of the public health risk associated with potential environmental sources of AIVs; and 3) To determine the potential for AIVs to infect mammals. This work will include AIVs from both wild and domestic birds, including highly pathogenic avian influenza viruses. The first aim relates to understanding potential sources for transmission (contaminated water, feces, environmental surfaces, avian tissue and carcasses). For each potential source, both experimental and field studies will be used to provide a standardized approach to evaluate and understand AIV environmental persistence, and attempts will be made to validate results with field collected samples. For the second aim we will conduct risk assessments related to potential human contact with AIVs through environmental exposure. [unreadable] Risk assessments and risk management plans will be developed in collaboration with the state health departments for two states (GA and MM). In this work we will provide an interactive framework to capture input from other state health departments as well as CDC. In aim 3 we will test for the ability of AIVs \o replicate in mammals through in vitro (MDCK) and in vivo (mice, ferrets, and cats) challenge. This aim is designed to add perspective, that is, to provide an estimate of potential outcome associated with AIV contact. The recent documentation of direct avian to human transmission of H5, H7, and H9 AIVs, and the mortality associated with HPAI H5N1 infections have redefined existing paradigms related to human influenza emergence. While this does not imply that such risks are new, these findings have resulted in a multitude of unanswered questions related to human AIV risks associated with direct or indirect avian contact. 'The information gained in this work will greatly increase our ability to prevent transmission opportunities and will provide guidance for better targeted surveillance. The information gained also has relevance to understanding AIV epidemiology in both human and animal populations and the control or elimination of domestic animal infections may be the most effective long-term approach to mitigate these public health risks. [unreadable] [unreadable] [unreadable] [unreadable]